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<TITLE>[Chapter 30] 30.17 java.util.Properties (JDK 1.0)</TITLE>
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<DIV CLASS=sect1>
<h2 CLASS=sect1><A CLASS="TITLE" NAME="JNUT2-CH-30-SECT-17">30.17 java.util.Properties (JDK 1.0)</A></h2>

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<h3 CLASS=sect2><A CLASS="TITLE" NAME="JNUT2-CH-30-SECT-17.1"></A></h3>
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<P CLASS=para>
This class is an extension of <tt CLASS=literal>Hashtable</tt> that allows
key/value pairs to be read from and written to a stream.
The <tt CLASS=literal>Properties</tt> class is used to implement the system
properties list, which supports user customization by
allowing programs to look up the value of named resources.

<P CLASS=para>
When you create a <tt CLASS=literal>Properties</tt> object, you may specify
another <tt CLASS=literal>Properties</tt> object that contains default
values. Keys (property names) and values are associated in
a <tt CLASS=literal>Properties</tt> object with the <tt CLASS=literal>Hashtable</tt>
method <tt CLASS=literal>put()</tt>. Values are looked up with
<tt CLASS=literal>getProperty()</tt>--if this method does not find the key
in the current <tt CLASS=literal>Properties</tt> object, it looks in
the default <tt CLASS=literal>Properties</tt> object that was passed to the
constructor method. A default value may also be specified
in case the key is not found at all.

<P CLASS=para>
<tt CLASS=literal>propertyNames()</tt> returns an enumeration of all
property names (keys) stored in the <tt CLASS=literal>Properties</tt>
object and (recursively) also all property names stored in
the default <tt CLASS=literal>Properties</tt> object associated with it.
<tt CLASS=literal>list()</tt> prints the properties stored in a
<tt CLASS=literal>Properties</tt> object. It is useful for debugging.
<tt CLASS=literal>save()</tt> writes a <tt CLASS=literal>Properties</tt> object to a
stream. <tt CLASS=literal>load()</tt> reads key/value pairs from a stream
and stores them in a <tt CLASS=literal>Properties</tt> object.

<DIV CLASS=screen>
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<PRE>
public class <tt CLASS=literal>Properties</tt> extends Hashtable {
    // <tt CLASS=literal>Public Constructors</tt>
            public <tt CLASS=literal>Properties</tt>();
            public <tt CLASS=literal>Properties</tt>(Properties <tt CLASS=literal>defaults</tt>);
    // <tt CLASS=literal>Protected Instance Variables</tt>
            protected Properties <tt CLASS=literal>defaults</tt>;
    // <tt CLASS=literal>Public Instance Methods</tt>
            public String <tt CLASS=literal>getProperty</tt>(String <tt CLASS=literal>key</tt>);
            public String <tt CLASS=literal>getProperty</tt>(String <tt CLASS=literal>key</tt>, String <tt CLASS=literal>defaultValue</tt>);
            public void <tt CLASS=literal>list</tt>(PrintStream <tt CLASS=literal>out</tt>);
        <b>1.1</b>public void <tt CLASS=literal>list</tt>(PrintWriter <tt CLASS=literal>out</tt>);
            public synchronized void <tt CLASS=literal>load</tt>(InputStream <tt CLASS=literal>in</tt>) throws IOException;
            public Enumeration <tt CLASS=literal>propertyNames</tt>();
            public synchronized void <tt CLASS=literal>save</tt>(OutputStream <tt CLASS=literal>out</tt>, String <tt CLASS=literal>header</tt>);
}
</PRE>
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<DIV CLASS=sect2>
<h3 CLASS=sect2><A CLASS="TITLE" NAME="JNUT2-CH-30-SECT-17.2">Hierarchy:</A></h3>

<P CLASS=para>
Object->Dictionary->Hashtable(Cloneable, Serializable)->Properties

</DIV>

<DIV CLASS=sect2>
<h3 CLASS=sect2><A CLASS="TITLE" NAME="JNUT2-CH-30-SECT-17.3">Passed To:</A></h3>

<P CLASS=para>
Properties(), 
System.setProperties(), 
Toolkit.getPrintJob()

</DIV>

<DIV CLASS=sect2>
<h3 CLASS=sect2><A CLASS="TITLE" NAME="JNUT2-CH-30-SECT-17.4">Returned By:</A></h3>

<P CLASS=para>
System.getProperties()

</DIV>

<DIV CLASS=sect2>
<h3 CLASS=sect2><A CLASS="TITLE" NAME="JNUT2-CH-30-SECT-17.5">Type Of:</A></h3>

<P CLASS=para>
Properties.defaults

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